Improve "limit" documentation for 2.1 unlimited queries

[cyrusae]

The SoQL Query documentation notes that version 2.1 endpoints' maximum is "unlimited" but doesn't specify if the parameter to provide to take advantage of that is the word "unlimited" or something else (e.g. for all I know it's "-1" under the same rationale as that being the logic some R packages use to denote no limit given). On an intuitive level the >> link after "unlimited" would seem to suggest that's where to go to find an answer but this is not the case. Could I suggest clarifying this in the docs, please?